Liquid crystal display apparatus having an input gradation set to have relationship along a gamma curve

ABSTRACT

In a liquid crystal display apparatus realizing a dual view display by bonding a liquid crystal panel and a parallax barrier, the parallax barrier separates display images by treating three pixels including R, G, and B pixels as one unit (one picture element). At this time, luminance variation due to crosstalk concentrates on a right-end pixel among the three pixels constituting the one picture element (in a case where each pixel receives data from a source line immediately on the left of the pixel). Accordingly, the right-end pixel is arranged to be a B pixel that has a low correlation with luminance information and in which influence of crosstalk is hard to be viewed. Further, an applied voltage to be supplied to the display pixel of the B (blue) color and an input gradation are set to have a relationship along a γ curve that makes luminance variation difficult to occur in a low luminance area.

PRIORITY STATEMENT

This application is a continuation under 35 U.S.C. §120 of applicationSer. No. 12/224,854 filed Sep. 8, 2008, which is a national stageApplication of PCT/JP2006/325212 filed Dec. 18, 2006 and claims priorityunder 35 U.S.C. §119 to Japanese Patent Application No. 2006-086207filed on Mar. 27, 2006, the contents of each of which are herebyincorporated herein by reference in their entirety and for all purposes.

TECHNICAL FIELD

The present invention relates to a liquid crystal display apparatus thatperforms a dual view display, in particular, to a liquid crystal displayapparatus that improves color reproducibility by reducing colorcrosstalk.

BACKGROUND ART

A problem of crosstalk is pointed out as a specific problem in aTFT-LCD. The crosstalk occurs because adjacent pixels are connected viaa parasitic capacitance. In other words, when an insulating filmintervenes between a transparent electrode and a source line, aparasitic capacitance is produced between the transparent electrode andthe source line. In the same manner, parasitic capacitances are producedbetween a gate line and the transparent electrode and between the sourceline and a common electrode, respectively. Due to influence of theseparasitic capacitances and a capacitance of a liquid crystal itself, anelectric potential of a display pixel becomes different from a desiredvoltage when a gate is turned OFF. Consequently, a display gradationbecomes different from a desired gradation.

In other words, at the moment a gate is high, a desired voltage isapplied to a display pixel that is connected to a TFT. However, when thegate is low, the pixel is connected to many peripheral electric circuitsvia parasitic capacitances. Because many of these peripheral electriccircuits are related to panel design, a driving voltage can be set inadvance in consideration of parasitic capacitances between the displaypixel and the peripheral electric circuits. Therefore, the crosstalkcaused by the parasitic capacitances that are formed between the displaypixel and the peripheral electric circuits can be compensated inadvance. However, an electric potential of a source line that drivesother display pixel cannot be determined in advance. Therefore, it isdifficult to compensate, in advance, crosstalk that is caused by othersource line.

As illustrated in FIG. 6( a), in a liquid crystal display apparatus,source lines Si (“i” is an integer) and gate lines Gj (j is an integer)are provided to be orthogonal. At each intersection of source lines Siand gate lines Gj, a display pixel 100 and a switching element 200 areprovided. Regarding a display pixel (A) among the display pixels 100,parasitic capacitances Csda, Csdb, Cgd, and Ccs are formed as follows. Adisplay pixel (B) indicates a display pixel that is adjacent to thedisplay pixel (A) in a direction along which a gate line is provided.

The details of the parasitic capacitances Csda, Csdb, Cgd, and Ccs areas follows:

the parasitic capacitance Csda: a parasitic capacitance that is formedbetween a source line S2 for driving display pixels (A) and the displaypixel (A);

the parasitic capacitance Csdb: a parasitic capacitance that is formedbetween a source line S3 for driving display pixels (B) and the displaypixel (A);

the parasitic capacitance Cgd: a parasitic capacitance that is formedbetween a gate line G2 for driving display pixels (A) and the displaypixel (A); and

the parasitic capacitance Ccs: a parasitic capacitance that is formedbetween a common electrode line and the display pixel (A).

A capacitance of the display pixel (A) itself is Cp and a voltage whichis applied to each gate line varies as shown in FIG. 6( b). Furthermore,while the display pixel (A) displays a G color, the display pixel (B)displays an R color or B color. In addition, in a case where a gradationof the display pixel (A) is LA and a gradation of the display pixel (B)is LB, LA # LB.

In this case, at the time at which the gate is high, when a drainvoltage +V(A) is applied to a liquid crystal part of the display pixel(A), a drain voltage −V (B) is applied to a liquid crystal part of thedisplay pixel (B). Then, when a next gate line is turned ON, −V (A) isapplied to the source line that drives the display pixel (A) and +V (B)is applied to a source line that drives the display pixel (B).

However, in the reality, the above-mentioned drain voltage is notapplied directly to the display pixel (A). A drain voltage that isvaried due to the influence of the parasitic capacitances is applied tothe display pixel (A). Specifically, an effective value Va of a voltagethat is applied to the display pixel (A) is represented by

Va=V(A)+(Csda*V(A)+Cgd*Vg+Csdb*V(B)+Ccs*Vc)/Cp,

where: Vg is a voltage that is applied to the gate line; and Vc is avoltage that is applied to an opposed electrode.

In this way, a voltage different from a desired drain voltage (A) isapplied to the display pixel (A).

The parasitic capacitances Csda, Cgd, and Ccs that are formed betweenthe display pixel (A) and the respective lines as mentioned above arepredictable at a stage of designing. Therefore, a drain voltage can beset in consideration of values of the parasitic capacitances.Accordingly, these parasitic capacitances do not have much influence ona display gradation of the display pixel (A).

However, the calculation formula of the effective voltage Va aboveincludes the parasitic capacitance Csdb and a drain voltage V(B). Inother words, the voltage Va is influenced by the source line that isconnected to the display pixel (B). This causes color crosstalk thatchanges the gradation of the display pixel (A) according to a displaygradation of the display pixel (B). For example, Patent Document 1discloses a method of solving the problem of the color crosstalk bycorrecting a display signal.

-   [Patent Document 1] Japanese Unexamined Patent Publication No.    202377/2005 (Tokukai 2005-202377 (published on Jun. 28, 2005))

DISCLOSURE OF INVENTION

However, in a conventional arrangement, a circuit and a process forcorrection become complicated.

Further, in a normal display mode in which the same image is displayedwith respect to all display directions, color crosstalk mentioned abovedoes not occur prominently for the following reason. That is, in anormal display state, image data of adjacent source lines are of thesame image. In regard to luminances of the image data of the adjacentsource lines, the image data that relate to R, G, and B colors arehighly correlated to one another. Therefore, even if crosstalk occurs,influence of the crosstalk is hard to appear in a visible image.

On the other hand, recently, a display mode (hereinafter, referred to asa dual view display) in which different images can be displayed withrespect to a plurality of display directions, respectively, is realized.In such a mode, a display panel is combined with a parallax barrier. Inthis dual view display, the problem of the crosstalk caused by othersource line becomes particularly prominent.

That is, in the dual view display, as illustrated in FIG. 7, a specificviewing angle is given, by a parallax barrier 120 that is providedoutside a display panel 110, to each of first and second images that areproduced by the display panel 110. This allows, as illustrated in FIG.8, displaying different images to a plurality of observers at differentobservation points, respectively.

In the dual view display, data of a different image is provided to eachsource line. The display is performed by separating, with the use of theparallax barrier, the different images into different directions,respectively. Accordingly, the image data of the adjacent source linesrelate to different images, respectively. As a result, the influence ofthe crosstalk to a visible image becomes large.

The present invention is attained in view of the above problem. Theobject of the present invention is to reduce, by a simple method, colorcrosstalk in a liquid crystal display that performs a dual view display.

In order to achieve the object above, in a liquid crystal displayapparatus of the present invention allowing a display mode in which adifferent image can be displayed with respect to each of a plurality ofdisplay directions to be realized by bonding a liquid crystal panel anda parallax barrier, the liquid crystal panel being provided with adisplay pixel including a switching element and a pixel electrode whichdisplay pixel corresponds to each intersection of a plurality of gatelines and a plurality of source lines: the parallax barrier separatesdisplay images viewed in different directions, respectively, bytreating, as one unit, three pixels including R, G, and B pixelsprovided in a direction in which a gate line is extended; in a casewhere, among the three pixels constituting the one unit, a pixel that ispresent at one end in the direction in which the gate line is extendedis a first display pixel and a pixel that is adjacent to the firstdisplay pixel and belongs to a display image that is separated into adisplay direction different from that of the first display pixel is asecond display pixel, a source line connected to the second displaypixel is adjacent to the first display pixel, the first display pixel isa display pixel of a B (blue) color, and an applied voltage to besupplied to the display pixel of the B (blue) color and an inputgradation are set to have a relationship along a γ curve that makesluminance variation difficult to occur in a low luminance area, comparedwith applied voltages supplied to display pixels of R (red) and G(green) colors, respectively.

According to the arrangement, in a pixel other than the first displaypixel, influence of crosstalk from other source line (other than asource line that supplies data to the pixel other than the first displaypixel) is hard to appear because the pixel other than the first displaypixel and a pixel that is connected to the other source line relate tothe same image and are highly correlated to each other. On the otherhand, influence of crosstalk that is caused by other source line (otherthan a source line that supplies data to the first display pixel) easilyappears in the first display pixel because the first display pixel and apixel that is connected to the other source line relates to imagesdifferent from each other and are not correlated.

In other words, influence of the crosstalk is concentrated in the firstdisplay pixel, by treating three pixels including R, G, and B pixels asone unit in separation of display images with the use of a parallaxbarrier at the time when a dual view display is performed. By arrangingthe first display pixel to be a B pixel that has a low correlation withluminance information, a change in a luminance due to the crosstalk canbe suppressed. Accordingly, influence of the crosstalk to a displayscreen can be reduced.

Further, the applied voltage to be supplied to the display pixel of theB (blue) color and the input gradation are set to have a relationshipalong a γ curve that makes luminance variation difficult to occur in alow luminance area (dark area), compared with applied voltages suppliedto display pixels of R (red) and G (green) colors, respectively (γ of Bis set large in the dark area).

This is for two reasons. A ratio of luminance variation due to crosstalkbecomes larger in a darker area. However, in an area that is darker thana certain level, even if the luminance changes at a large ratio, theluminance variation becomes insensible. In a bright area, because theratio of the luminance variation is small, it is clearly not necessaryto care about color crosstalk. That is, influence of the color crosstalkis the largest in a half-tone area that is relatively dark. Therelatively dark area can be avoided by setting γ so that γ on a lowgradation side is relatively large. γ may be separately set such that,for example, γ of a gradation not more than a certain level is 2.5 and γof a gradation not less than the certain level is 2.2. In particular, itis preferable to set γ so that γ of a gradation not less than 128^(th)gradation is 2.2 and γ of a gradation not more than 128^(th) gradationvaries sequentially from 2.2 towards 2.5 that is γ at 0^(th) gradation.This is for the purpose of realizing a gradation display characteristicthat is relatively sequential and smooth even in a case where thecrosstalk tends to influence the gradation display. The γ of 2.5 that isset here is one example. The γ may be set as appropriate according to anapplication, as long as a video image does not deviate largely from theimage in a case where γ is set to 2.2 as in a general case.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1( a) is a plan view showing an embodiment of the present inventionand a positional relationship of a picture element and R, G, and Bpixels in a color liquid crystal display apparatus.

FIG. 1( b) is a diagram showing the embodiment of the present inventionand illustrating an example of a structure in a case where separation iscarried out by providing a barrier light-blocking layer and treatingthree pixels including R, G, and B pixels as one unit.

FIG. 2 is a cross sectional view schematically illustrating anarrangement of the color liquid crystal display apparatus.

FIG. 3 is a graph illustrating an example of a setting of a γ curve.

FIG. 4 is a block diagram schematically illustrating a structure of thecolor liquid crystal display apparatus.

FIG. 5 is a block diagram schematically illustrating an example of anarrangement of the color liquid crystal display apparatus which exampleis different from the arrangement of FIG. 4.

FIG. 6( a) is a diagram illustrating an arrangement of a display panelin a conventional liquid crystal display apparatus.

FIG. 6( b) is a diagram illustrating a state in which a voltage isapplied to a gate line.

FIG. 7 is a diagram illustrating an effect of giving a viewing anglewith the use of a viewing barrier in a dual view display.

FIG. 8 is a diagram illustrating a relationship between a display screenand observers in a case where a dual view display is performed.

BEST MODE FOR CARRYING OUT THE INVENTION

One embodiment of the present invention is explained with reference todrawings.

First, FIG. 2 schematically illustrates an arrangement of a liquidcrystal display apparatus 1 of the present embodiment. The liquidcrystal display apparatus 1 is a color liquid crystal display apparatusthat is capable of performing a dual view display. As illustrated inFIG. 2, roughly, the liquid crystal display apparatus 1 includes adisplay panel 100, a parallax barrier 110, and a backlight 120.

The backlight 120 includes a light source 121 and a reflecting section122. The reflecting section 122 reflects light that is emitted from thelight source 121, so that light is irradiated on the display panel 100.Examples of the light source 121 are an LED (Light Emitting Diode), aCCFT (Cold Cathode Fluorescent Tube), and a CCFL (Cold CathodeFluorescent Lump).

The display panel 100 is an active matrix type liquid crystal displaypanel in which a liquid crystal layer 103 made of a nematic liquidcrystal is sandwiched between a TFT (Thin Film Transistor) substrate 101and a CF (Color Filter) substrate 102 that are provided so as to faceeach other.

The TFT substrate 101 is provided with a plurality of source lines and aplurality of gate lines each intersecting each of the source lines. Ateach intersection of a source line and a gate line, a pixel is provided.As illustrated in FIG. 2, the pixels are provided along a direction inwhich a data signal line (not shown) is extended so that pixels of aleft picture element line for an image display to a left side (an imagedisplay to a left side of the display apparatus) is providedalternatively with pixels of a right picture element line for an imagedisplay to a right side (an image display to a right side of the displayapparatus). As illustrated in FIG. 1( a), each of the left pictureelement and the right picture element are formed so as to have R, G, andB pixels as one set.

On the CF substrate 102, a color filter layer (not shown) is provided.In the color filter layer, R, G, and B filters are provided so as tocorrespond to respective pixels.

On opposed surfaces of the TFT substrate 101 and the CF substrate 102are provided with alignment films (not shown), respectively. Thealignment films have been subjected to alignment treatments indirections that are substantially perpendicular to each other,respectively. A surface of the TFT substrate 101 on a side provided withthe backlight 120 is provided with a polarizer 104.

The parallax barrier 110 is made of a barrier glass 111 and a barrierlight-blocking layer 112. The barrier light-blocking layer 112 is formedby patterning a metal layer or a resin layer on the barrier glass 111.On a display surface side of the barrier glass 111 (an opposite sidewith respect to a side provided with the backlight 120), a polarizer 23is provided.

The barrier light-blocking layer 112 is provided so as to form, forexample, striped lines in a direction parallel to a direction in whichthe picture element lines are extended. A material of the barrierlight-blocking layer 112 is not specifically limited. The barrierlight-blocking layer 112 may be formed, for example, by using aphotosensitive resin in which black pigments are dispersed or bypatterning a metal thin film.

Further, each line of the barrier light-blocking layer 112 is providedso as to correspond to each picture element line of the display panel100. Namely, the barrier light-blocking layer 112 separates a rightimage and a left image by treating three pixels including R, G, and Bpixels as one unit. FIG. 1( b) illustrates an example of a structure ina case where separation is performed by providing the barrierlight-blocking layer 112 and treating three pixels including R, G, and Bpixels as one unit.

In this way, as illustrated in FIGS. 1( a) and 1(b), the separation of aright image and a left image with the use of the barrier light-blockinglayer 112 is performed by treating the three pixels (corresponding to R,G, and B pixels) as one unit. In such a case, in a structure in whichdata is supplied to each pixel from a source line on the left side ofthe pixel, crosstalk that is caused by other source line largelyinfluences only a pixel at the right end among the three pixelsconstituting one unit.

In other words, in the above-mentioned structure, a left-end pixel (Rpixel in FIGS. 1( a) and 1(b)) among the three pixels constituting oneunit is influenced by crosstalk from a source line that supplies data toa pixel (a center pixel among the three pixels constituting one unit: Gpixel in FIGS. 1( a) and 1(b)) immediately on the right of the left-endpixel. However, the left-end pixel and the center pixel relate to anidentical image. Therefore, the left-end pixel and the center pixel arehighly correlated to each other. Accordingly, even when crosstalkoccurs, influence of the crosstalk is hard to appear in a visible image.In the same manner, although the center pixel is influenced by crosstalkfrom a source line that supplies data to a right-end pixel (B pixel inFIGS. 1( a) and 1(b)) immediately on the right of the center pixel, thecrosstalk is hard to appear in a visible image.

On the other hand, the right-end pixel is influenced by crosstalk from asource line that supplies data to another left-end pixel immediately onthe right of the right-end pixel. Here, the right-end pixel and theanother left-end pixel relates to different images, respectively.Therefore, display data of the right-end pixel and the another left-endpixel are not correlated to each other. Therefore, the right-end pixelis influenced by crosstalk more than the left-end pixel and the centerpixel.

The above explanation assumes a structure in which data is supplied toeach pixel from a source line that is provided on the left of the pixel.Accordingly, the right-end pixel is largely influenced by crosstalk.However, in the present invention, it is assumed that, among threepixels constituting one unit, (i) a first display pixel is a pixelprovided to one end in a direction in which the gate line is extendedand (ii) a second display pixel is a pixel that is adjacent to the firstdisplay pixel and belongs to a display image separated into a displaydirection different from that of a display image to which the firstdisplay pixel belongs. On this assumption, the first display pixel is apixel that is largely influenced by crosstalk. In such a case, an endpixel on a side adjacent to a source line that connects to the seconddisplay pixel is the first display pixel.

Here, the present invention has a feature such that the first displaypixel is arranged to be a B pixel, as illustrated in FIGS. 1( a) and1(b), so that influence of crosstalk to the first display pixel isreduced.

That is, the larger a change in luminance due to crosstalk that iscaused by other source line is, the more easily the crosstalk is viewed.On the other hand, in regard to correlation of each of R, G, and Bcolors and a luminance, R and G colors have a high correlation withluminance information while B color has a low correlation with luminanceinformation. Accordingly, by arranging the first display pixel to whichthe influence of crosstalk is large to be a B color pixel whosecorrelation with luminance information is low, a change in the luminancedue to crosstalk can be suppressed and influence of the crosstalk to adisplay screen can be reduced.

In other words, in the liquid crystal display apparatus 1 of the presentembodiment, separation of display images with the use of a parallaxbarrier is performed by treating the three pixels including R, G, and Bpixels as one unit, when a dual view display is performed. Thisconcentrates the influence of the crosstalk in the first display pixel.Further, by arranging the first display pixel to be a B pixel that has alow correlation with luminance information, a change in the luminancecan be suppressed, thereby reducing the influence to the display screen.

Further, in the liquid crystal display apparatus 1, γ correction capableof further suppressing influence of crosstalk is carried out in thefirst display pixel in which the influence of the crosstalk is large.

Specifically, when the γ correction is carried out with respect to dataof a B color, a γ curve of the data is set deep so that influence ofcrosstalk in a dark area becomes hard to see. This is because a colorshift due to a change in luminance is more easily seen in a dark areathan in a bright area. By setting a γ value of B in a dark area to besmall, a change in luminance in the display region of B becomes hard tobe produced even when a potential changes due to an adjacent source line(R).

FIG. 3 as follows illustrates an example of a setting of the γ curve. Acurve illustrated by a solid line in FIG. 3 shows a general γ curve thatis generally used. However, in the liquid crystal display apparatus 1 ofthe present embodiment, the curve illustrated by the solid line in FIG.3 is used for γ correction with respect to data of R and G colors.Moreover, a curve illustrated by a dotted line in FIG. 3 shows a curvethat is used for the γ correction with respect to data of a B color.

The following explains an example of a circuit configuration thatcarries out γ correction with respect to an input gradation signal andgenerates a write signal for a liquid crystal panel in the liquiddisplay apparatus 1 of the present embodiment.

As illustrated in FIG. 4, the liquid crystal display apparatus 1includes a display panel 10, a gate driving section 11, a source drivingsection 12, a common electrode driving section 13, and a control section14.

The display panel 10 (detailed illustration thereof is omitted here)includes m gate lines that are parallel to each other, n source linesthat are parallel to each other, and pixels arranged in a matrix. Eachpixel is formed in a region that is surrounded by two of the gate linesadjacent to each other and two of the source lines adjacent to eachother.

The gate driving section 11 sequentially generates scanning signals thatare to be provided to the gate lines to which pixels in each line areconnected, according to gate clock signals and gate start pulses thatare outputted from the control section 14.

The source driving section 12 samples image data signals DAT inaccordance with the source clock signals and the source start pulsesthat are outputted from the control section 14, and outputs image dataobtained to the source lines to which pixels in each line are connected.

The control section 14 is a circuit that generates and outputs, inaccordance with a sync signal and an image data signal DAT that areinputted, various kinds of control signals that control operations ofthe gate driving section 11 and the source driving section 12. Asmentioned above, clock signals, start pulses, the image data signalsDAT, and the like are prepared as control signals that are outputtedfrom the control section 14.

Each pixel of the display panel 10 includes a switching element such asa TFT, and a liquid crystal capacitor. In such a pixel, a gate of theTFT is connected to a gate line. Moreover, a source line is connected toone electrode of the liquid crystal capacitor via a drain and a sourceof the TFT. Further, the other end of the liquid crystal capacitor isconnected to a common electrode line that is common to all the pixels.The common electrode driving section 13 is arranged to supply a voltageto be applied to the common electrode line.

In the liquid crystal display apparatus 1, the gate driving section 11selects a gate line. Then, the source driving section 12 outputs, toeach source line, an image data signal DAT for a pixel corresponding toa combination of the gate line and a source line that are beingselected. This allows each image data to be written into the pixel thatis connected to the gate line. Further, the gate driving section 11sequentially selects the gate lines and the source driving section 12outputs image data to the source lines. As a result, the respectiveimage data is written into all of the pixels of the display panel 10,and an image corresponding to the image data signals DAT is displayed onthe display panel 10.

Here, the image data sent from the control section 14 to the sourcedriving section 12 is transmitted as image data signals DAT in atime-sharing manner. The source driving section 12 extracts each imagedata from the image data signals DAT according to timing on the basis ofa source clock signal, an inversion source clock signal, and a sourcestart pulse that become timing signals, and transmits the extractedimage data to each pixel.

Next, the γ correction in the liquid crystal display apparatus 1 isexplained.

For example, in the liquid crystal display apparatus that performsmulti-gradation display including 256 gradations, 256 kinds of appliedvoltage values are required. However, in practice, it is not possible toinclude power source voltages that correspond to all of these gradationvoltages, respectively. Therefore, in general, several kinds ofreference voltages are prepared as the power source voltages. Bydividing these reference voltages by resistance dividing means intopartial voltages, applied voltages (gradation quasi-voltages) thatcorrespond to all the gradations, respectively, are generated.

The resistance dividing means are composed of many resistors connectedin series. An applied voltage that is obtained at each of connectingpoints of respective resistors is extracted according to switchingcontrol in accordance with the image data signal DAT. That is, the imagedata signal DAT is, for example, an 8-bit digital signal (in case wherethe number of gradations is 256). A desired applied voltage can beextracted from the 256 kinds of applied voltages, by carrying out8-stage switching control with the use of each bit signal. Note thatsuch resistance dividing means is a publicly known arrangement that isconventionally used in a liquid crystal display of a voltage modulationsystem. The source driving section 12 includes a gradation voltagegenerating circuit (not shown) that employs the resistance dividingmeans as mentioned above.

Here, a relationship between the gradation and the applied voltage inthe liquid crystal apparatus is not proportional, but has a specific γcurve. Accordingly, a resistance value of each resistor is set so thatthe resistance dividing means of the gradation voltage generatingcircuit obtains a gradation voltage along the γ curve. In this way, theresistance value of each resistor is not set so that the referencevoltages are proportionally distributed.

In the liquid crystal display apparatus 1, the gradation voltagegeneration circuit that supplies a gradation voltage to a source linethat is connected to a B-color pixel should be set so that it becomespossible to obtain a gradation voltage along γ curve with respect to theB-color data in FIG. 3.

A method of the γ correction in the liquid crystal display apparatus 1is not limited to this. The γ correction may be carried out by carryingout data conversion with respect to image data of a B-color. The γcorrection in such a case is explained with reference to FIG. 5.

In this case, as illustrated in FIG. 5, the liquid crystal displayapparatus 1 further includes a γ correction section 15 and a lookuptable 16. In other words, the γ correction section 15 carries out dataconversion with reference to the lookup table 16 so that image data of aB-color pixel stays along the γ curve with respect to the B-color datain FIG. 3.

Specifically, among data signal's DAT that are inputted into the controlsection 14, image data of R and G colors are directly sent to the sourcedriving section 12. However, image data of a B color is subjected todata conversion with the use of the γ correction section 15 and thelookup table 16, and then sent to the source driving section 12.

The lookup table 16 stores an input gradation level and an outputgradation level so that the input gradation level and the outputgradation level correspond to each other. When an input gradation levelof the image data signal DAT is inputted from the γ correction section15, an output gradation level corresponding to this input gradationlevel is read out. The γ correction section 15 outputs the outputgradation level that is read out from the lookup table 16 to the sourcedriving section 12.

For example, in the liquid crystal display apparatus 1, an ideal appliedvoltage along the γ curve with respect to the data of a B color in FIG.3 is in a range of V′ 0 to V′ 255 (in the case of 256-gradationdisplay). The following Table 1 is shows a relationship between (i) eachof the applied voltages V′ 0 to V′ 255 and (ii) an applied voltage amongthe applied voltages V0 to V255 that are generated by the resistancedividing means for carrying out the 256 gradation display which appliedvoltage is the closest to the each of the applied voltages V′ 0 to V′255. Note that the Table 1 below shows an example in which a gradationequal to or less than 128^(th) gradation is set to γ 2.5. Moreover, inthe Table 1, the output gradation indicates a voltage that correspondsto the output gradation.

TABLE 1 IG OG(B) 0 0 1 0 2 1 3 1 4 2 5 2 6 3 7 4 8 5 9 5 10 6 11 7 12 813 9 14 9 15 10 16 11 17 12 18 13 19 14 20 14 21 15 22 16 23 17 24 18 2519 26 20 27 21 28 22 29 23 30 23 31 24 32 25 33 26 34 27 35 28 36 29 3730 38 31 39 32 40 33 41 34 42 35 43 36 44 37 45 38 46 39 47 40 48 41 4942 50 43 51 44 52 45 53 46 54 47 55 48 56 49 57 50 58 51 59 52 60 54 6155 62 56 63 57 64 58 65 59 66 60 67 61 68 62 69 63 70 64 71 65 72 66 7367 74 68 75 69 76 71 77 72 78 73 79 74 80 75 81 76 82 77 83 78 84 79 8580 86 81 87 83 88 84 89 85 90 86 91 87 92 88 93 89 94 90 95 91 96 92 9793 98 95 99 96 100 97 101 98 102 99 103 100 104 101 105 102 106 103 107104 108 106 109 107 110 108 111 109 112 110 113 111 114 112 115 113 116114 117 115 118 117 119 118 120 119 121 120 122 121 123 122 124 123 125124 126 125 127 126 128 128 129 129 130 130 131 131 132 132 133 133 134134 135 135 136 136 137 137 138 138 139 139 140 140 141 141 142 142 143143 144 144 145 145 146 146 147 147 148 148 149 149 150 150 151 151 152152 153 153 154 154 155 155 156 156 157 157 158 158 159 159 160 160 161161 162 162 163 163 164 164 165 165 166 166 167 167 168 168 169 169 170170 171 171 172 172 173 173 174 174 175 175 176 176 177 177 178 178 179179 180 180 181 181 182 182 183 183 184 184 185 185 186 186 187 187 188188 189 189 190 190 191 191 192 192 193 193 194 194 195 195 196 196 197197 198 198 199 199 200 200 201 201 202 202 203 203 204 204 205 205 206206 207 207 208 208 209 209 210 210 211 211 212 212 213 213 214 214 215215 216 216 217 217 218 218 219 219 220 220 221 221 222 222 223 223 224224 225 225 226 226 227 227 228 228 229 229 230 230 231 231 232 232 233233 234 234 235 235 236 236 237 237 238 238 239 239 240 240 241 241 242242 243 243 244 244 245 245 246 246 247 247 248 248 249 249 250 250 251251 252 252 253 253 254 254 255 255 (IG: INPUT GRADATION, OG(B): OUTPUTGRADATION (B))

In other words, in case where γ correction of the image data of a Bcolor is to be performed along the γ curve with respect to the data of aB color in FIG. 3, for example, an applied voltage V1 that is generatedby the resistance dividing means becomes the closest to an ideal appliedvoltage V′3 with respect to display of the input gradation level 3.Accordingly, the lookup table 16 should be set to have an outputgradation level of 1 in a case where the input gradation level of theimage data of a B color is 3.

As mentioned above, in a liquid crystal display apparatus of the presentinvention allowing a display mode in which a different image can bedisplayed with respect to each of a plurality of display directions tobe realized by bonding a liquid crystal panel and a parallax barrier,the liquid crystal panel being provided with a display pixel including aswitching element and a pixel electrode which display pixel correspondsto each intersection of a plurality of gate lines and a plurality ofsource lines: the parallax barrier separates display images viewed indifferent directions, respectively, by treating, as one unit, threepixels including R, G, and B pixels provided in a direction in which agate line is extended; in a case where, among the three pixelsconstituting the one unit, a pixel that is present at one end in thedirection in which the gate line is extended is a first display pixeland a pixel that is adjacent to the first display pixel and belongs to adisplay image that is separated into a display direction different fromthat of the first display pixel is a second display pixel, a source lineconnected to the second display pixel is adjacent to the first displaypixel, the first display pixel is a display pixel of a B (blue) color,and an applied voltage to be supplied to the display pixel of the B(blue) color and an input gradation are set to have a relationship alonga γ curve that makes luminance variation difficult to occur in a lowluminance area, compared with applied voltages supplied to displaypixels of R (red) and G (green) colors, respectively.

According to the arrangement, in a pixel other than the first displaypixel, influence of crosstalk from other source line (other than asource line that supplies data to the pixel other than the first displaypixel) is hard to appear because the pixel other than the first displaypixel and a pixel that is connected to the other source line relate tothe same image and are highly correlated to each other. On the otherhand, influence of crosstalk that is caused by other source line (otherthan a source line that supplies data to the first display pixel) easilyappears in the first display pixel because the first display pixel and apixel that is connected to the other source line relates to imagesdifferent from each other and are not correlated.

In other words, influence of the crosstalk is concentrated in the firstdisplay pixel, by treating three pixels including R, G, and B pixels asone unit in separation of display images with the use of a parallaxbarrier at the time when a dual view display is performed. By arrangingthe first display pixel to be a B pixel that has a low correlation withluminance information, a change in a luminance due to the crosstalk canbe suppressed. Accordingly, influence of the crosstalk to a displayscreen can be reduced.

Further, the applied voltage to be supplied to the display pixel of theB (blue) color and the input gradation are set to have a relationshipalong a γ curve that makes luminance variation difficult to occur in alow luminance area (dark area), compared with applied voltages suppliedto display pixels of R (red) and G (green) colors, respectively (γ of Bis set large in the dark area).

This is for two reasons. A ratio of luminance variation due to crosstalkbecomes larger in a darker area. However, in an area that is darker thana certain level, even if the luminance changes at a large ratio, theluminance variation becomes insensible. In a bright area, because theratio of the luminance variation is small, it is clearly not necessaryto care about color crosstalk. That is, influence of the color crosstalkis the largest in a half-tone area that is relatively dark. Luminancevariation in the relatively dark area can be avoided by setting γ sothat γ on a low gradation side is relatively large. γ may be separatelyset such that, for example, γ of a gradation not more than a certainlevel is 2.5 and γ of a gradation not less than the certain level is2.2. In particular, it is preferable to set γ so that γ of a gradationnot less than 128^(th) gradation is 2.2 and γ of a gradation not morethan 128^(th) gradation varies sequentially from 2.2 towards 2.5 that isγ at 0^(th) gradation. This is for the purpose of realizing a gradationdisplay characteristic that is relatively sequential and smooth even ina case where the crosstalk tends to influence the gradation display. Theγ of 2.5 that is set here is one example. The γ may be set asappropriate according to an application, as long as a video image doesnot deviate largely from the image in a case where γ is set to 2.2 as ina general case.

Moreover, the liquid crystal display apparatus may include: a referencevoltage generating circuit that generates an applied voltage to besupplied to the display pixel of the B (blue) color, the referencevoltage generating circuit performing an input gradation signal/appliedvoltage conversion along the γ curve that makes the luminance variationdifficult to occur in the low luminance area.

According to the arrangement, an input gradation signal-applicationvoltage relationship can be arranged along an optimum γ curve.

Further, the liquid crystal display apparatus may include: a dataconverting section converting input gradation data of the B (blue) colorso as to generate an output gradation signal to be outputted to a datadriving section, the data converting section carrying out dataconversion so that an output gradation signal-applied voltagerelationship is along the γ curve that makes the luminance variationdifficult to occur in the low luminance area

According to the arrangement, it is not necessary to separately have areference voltage generating circuit for a B (blue) color and areference voltage generation circuit for R (red) and G (green) colors.Therefore, the gradation signal-applied voltage relationship can bearranged along an appropriate γ curve in a simple arrangement.

1. A display apparatus comprising: a display panel including displaypixels of at least a red (R) color, green (G) color, and blue (B) color,and which a set of at least one R color display pixel, at least one Gcolor display pixel, and at least one B color display pixel serves as aunit of the display pixels; and a parallax barrier disposed on thedisplay panel, configured to separate images that are displayed on thedisplay panel and viewed in different directions, an applied voltage tobe supplied to the display pixel of the B color and an input gradationbeing set to have a relationship along a γ curve, the applied voltage tobe applied to the display pixel of the B color producing a luminancehaving a lesser variation than luminances produced by applied voltagessupplied to display pixels of R and G colors, respectively.
 2. Thedisplay apparatus as set forth in claim 1, further comprising: areference voltage generating circuit that generates an applied voltageto be supplied to the display pixel of the B color, the referencevoltage generating circuit performing an input gradation signal/appliedvoltage conversion along the γ curve.
 3. The display apparatus as setforth in claim 1, further comprising: a data converting sectionconverting input gradation data of the B color so as to generate anoutput gradation signal to be outputted to a data driving section, thedata converting section carrying out data conversion so that an outputgradation signal-applied voltage relationship is along the γ curve.
 4. Adisplay apparatus comprising: a plurality of gate lines; a plurality ofsource lines intersecting the plurality of gate lines, the intersectionscorresponding to locations of at least a first plurality of pixels and asecond plurality of pixels; at least a first picture element having thefirst plurality of pixels, the first picture element being configured todisplay a first image; and at least a second picture element having thesecond plurality of pixels, the second picture element configured todisplay a second image, the second image being in a different displaydirection than the first image; and a reference voltage generatingcircuit configured to generate an applied voltage for the first pixel ofthe first plurality of pixels based on an input gradation signal and afirst γ curve, the reference voltage generating circuit configured togenerate an applied voltage for the first pixel of the second pluralityof pixels based on an input gradation signal and a second γ curve, thesecond γ curve being different than the first γ curve.
 5. The displayapparatus of claim 4, wherein the first plurality of pixels includesred, green and blue pixels, and the second plurality of pixels includesred, green and blue pixels.
 6. The display apparatus of claim 5, whereinthe first pixel of the first plurality of pixels is a blue pixel and thefirst pixel of the second plurality of pixels is a red pixel.
 7. Adisplay apparatus comprising: a display panel including display pixelsof at least a red (R) color, green (G) color, and blue (B) color, andwhich a set of at least one R color display pixel, at least one G colordisplay pixel, and at least one B color display pixel serves as a unitof a plurality of display pixels; a parallax barrier disposed on thedisplay panel, configured to separate images that are displayed on thedisplay panel and viewed in different directions; at least a firstpicture element having a first plurality of display pixels, the firstpicture element being configured to display a first image; at least asecond picture element having a second plurality of display pixels, thesecond picture element configured to display a second image, the secondimage being in a different display direction than the first image; and areference voltage generating circuit configured to generate an appliedvoltage for the first pixel of the first plurality of pixels based on aninput gradation signal and a first γ curve, the reference voltagegenerating circuit configured to generate an applied voltage for thefirst pixel of the second plurality of pixels based on an inputgradation signal and a second γ curve, the second γ curve beingdifferent than the first γ curve.